Halos, starbursts

Can anyone help? For the past few months I've been experiencing halos around bright light sources, particularly at night, and starbursts around car headlights and computer LEDs. I also get some ghosting around green traffic lights.

I've been to the optician who checked me for glaucoma and cataracts. I had neither. Retinal photographs were also fine. They checked me for dry eye and for corneal scarring. There was no problem here either. I don't have astigmatism.

So what else could it be? Some other problem with my tear film? Corneal swelling? If I look through a pinhole, the starbursts disappear.

I also have incredibly tight upper neck muscles. Could they be impacting on some eye related nerve?